| 年度 | 实际值 |
|---|---|
| 1992 | 8.6 |
| 1993 | 13.9 |
| 1994 | |
| 1995 | 13.67 |
| 1996 | 12.6 |
| 1997 | 8.35 |
| 1998 | 1.75 |
| 1999 | 7.62 |
| 2000 | 28.27 |
| 2001 | 5.66 |
| 2002 | 9.19 |
| 2003 | 15.71 |
| 2004 | 10.63 |
| 2005 | 12.62 |
| 2006 | 13.12 |
| 2007 | 9.34 |
| 2008 | 13.88 |
| 2009 | |
| 2010 | 10.29 |
| 2011 | 5.3 |
| 2012 | 3.4 |
| 2013 | 9.9 |
| 2014 | 10.6 |
| 2015 | 29.32 |
| 2016 | 14.3 |
| 2017 | 12.51 |
| 2018 | 12.51 |